A spool for strip-type wound material (paper roll) in a version for correct-sided insertion into a printer in accordance with the generic type is known from EP Application No. 0 401 036, filed Jun. 01, 1990, by Takeuchi, et al. with the spool having a tapered mounting bore for the purpose of correct-sided fitting on two mounting journals of the apparatus that are axially separated from one another.
The disadvantage of this is that the contact surface formed between the mounting bore of the spool and the two mounting journals of the apparatus is relatively small, which leads to heavy strain on the affected bearing parts when the wound material has a high weight. In addition, the requirement for and the use of two mounting journals makes the configuration of the apparatus complicated. Furthermore, spools with differing wound materials, or with the same wound material but opposite winding direction relative to the tapered mounting bore determining their insertion direction, cannot be distinguished when they are fitted on the mounting journals and their use in the correct-sided operating position on the mounting journal relative to the wound material is therefore only guaranteed by using additional scanning means on one of the flange disks and an expensive electronic or opto-electronic scanning device inside the apparatus.
The object underlying the present invention is therefore to provide a spool of the generic type that on the one hand has a simple and inexpensive structure and permits a simple, compact, and inexpensive configuration of the apparatus receiving the spool, and on the other hand is versatile in use, i.e. for wound materials of differing winding directions and materials, while at the same time permitting safe and simple handling of the spools with differing wound materials and ensuring the respectively predetermined operating position of the spool inside the apparatus, with functioning in an automated environment also being assured.
The object is attained in accordance with the invention by a spool in that at least one insertion direction/position determining means at a distance radially from the mounting bore is arranged on the outside of at least one of the flange disks of the spool such that wrong-sided fitting of the spool on a mounting journal is recognizable and an axial movement of the spool into its predetermined operating position on the mounting journal is preventable when it has been fitted on the wrong side. The insertion direction/position determining means on the flange disk is advantageously configured as a projection or depression concentrically arranged about the central axis, in particular about the mounting bore of the spool.
Furthermore, first and second annular insertion direction/position determining means are advantageously provided on one of the flange disks of the spool and are arranged concentrically and at a radially differing distance to the mounting bore, or a first or second annular insertion direction/position determining means is provided on each of the flange disks of the spool and is arranged concentrically and at a radially differing distance to the mounting bore, with the insertion direction/position determining means each being assigned to one winding direction of the wound material or to one type of wound material.